Mailing-List: contact dev-help@harmony.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@harmony.apache.org
Received-SPF: pass (nike.apache.org: domain of gcjhd-harmony-dev@m.gmane.org
 designates 80.91.229.2 as permitted sender)
To: dev@harmony.apache.org
From: Egor Pasko <egor.pasko@gmail.com>
Subject: Re: [general] GSoC 2008 Refactor Java Bytecode Translator
Date: 01 Apr 2008 02:53:06 +0400
Lines: 82
Message-ID: <0vqmyoeeca5.fsf@gmail.com>
References: <884d1faa0803192322o7b9f58dfja181970fbe2f882e@mail.gmail.com>
 <0vqmyojgn54.fsf@gmail.com>
 <c30d70960803280956v1460b2cegaf7a2e5fe600ae11@mail.gmail.com>
 <0vqiqz6hg79.fsf@gmail.com> <0vqej9uhcnc.fsf@gmail.com>
 <884d1faa0803282142o1507767ejed736d455cf6bea5@mail.gmail.com>
 <0vqabkhhgrh.fsf@gmail.com>
 <884d1faa0803300533h181c323cv4a8d5ee9875ff059@mail.gmail.com>
 <884d1faa0803301138v1e84b867wfcc907cf86ccd20c@mail.gmail.com>
 <0vq4panf42u.fsf@gmail.com>
 <884d1faa0803310936i5703e01ck71798eff11a88993@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.4
Sender: news <news@ger.gmane.org>

On the 0x418 day of Apache Harmony Okonechnikov Konstantin wrote:
> On 31 Mar 2008 16:52:41 +0400, Egor Pasko <egor.pasko@gmail.com> wrote:
> >
> > On the 0x417 day of Apache Harmony Okonechnikov Konstantin wrote:
> > > In addition to previous letter:
> > > - I removed DoSimplify flag from IrBuilderFlags and all code connected
> > to it
> > > , but didn't removed simplifier yet.
> > > First reason is that,there are some problems with removing
> > simplification
> > > from
> > >      IRBuilder::genTauCheckNull(Opnd* opnd, bool &alwaysThrows)
> > >      IRBuilder::genTauCheckZero(Opnd* opnd, bool &alwaysThrows)
> > >      IRBuilder::simplifyTauCheckDivOpnds(Opnd* src1, Opnd* src2, bool
> > > &alwaysThrows)
> >
> >
> > what is with these methods?
> >
> >
> > > Well, I figured out that simply removing simplification here doesn't
> > work
> > > :)
> >
> >
> > what happens? :)
> 
> 
> It looks like some dark magic or maybe late night hours
> :), now everyting seems to be OK, I removed
> simplification. Nevertheless, I beware of nasty warning inside
> IRBuilder::genTauCheckNull(...):
> ...
> // Not advisable to turn off simplification of checknull because
> // IRBuilder calls genTauCheckNull redundantly many times

I have no idea what this means, but I will take a look! plz, remind me
if I do not do it in a couple of days :)

> // ...then it does simplify without asking the flag
> ...
> 
> I am working now on removing propgate copy and SCE. Testing on HelloWorld.
> If there were such code:
> 
>     Opnd* IRBuilder::genAdd(Type* dstType, Modifier mod, Opnd* src1, Opnd*
> src2) {
>         src1 = propagateCopy(src1);
>         src2 = propagateCopy(src2);
>         Operation operation(Op_Add, dstType->tag, mod);
>         uint32 hashcode = operation.encodeForHashing();
>         Opnd* dst = lookupHash(hashcode, src1, src2);
>         if (dst) return dst;
>         if (!dst) {
>              dst = createOpnd(dstType);
>              Inst *newi = instFactory->makeAdd(mod, dst, src1, src2);
>              appendInst(newi);
>         }
>         insertHash(hashcode, src1, src2, dst->getInst());
>         return dst;
>      }
> 
> It becomes like this:
> 
> Opnd* IRBuilder::genAdd(Type* dstType, Modifier mod, Opnd* src1, Opnd* src2)
> {
>         Operation operation(Op_Add, dstType->tag, mod);
>         Opnd* dst = createOpnd(dstType);
>         Inst *newi = instFactory->makeAdd(mod, dst, src1, src2);
>         appendInst(newi);
>         return dst;
>      }
> 
> Is everything OK?

Let's not remove copy propagation, it does not make the code
difficult, does not add lots of lines, but still very functional.

OK?

-- 
Egor Pasko